What should engineers pay attention to when planning sensors?

The planning of good sensors is the result of experience plus skills. It is generally understood that a sensor transforms a physical quantity through a circuit into a physical quantity that can be expressed in another intuitively expressible form. For example, a signal such as a higher voltage and current that depends only on the measured physical quantity is displayed and displayed. Therefore, the need to pay attention to a few points:

1. The measured physical quantity is generally very small, and generally has conversion noise inherent to the physical transformation element of the sensor. For example, the signal strength of the sensor at the magnification is 0.1~1uV, and the background noise signal at this moment has such a large level, even annihilating it. How to take out the useful signal as much as possible and reduce the noise is the primary treatment of sensor planning.

2, the sensor circuit must be simple and succinct. Imagine an extended loop with a 2-stage active filter with a 2-stage active filter that expands the signal while also amplifying the noise. If the noise does not significantly deviate from the useful signal spectrum, then both filters are expanded at the same time. The resulting signal to noise ratio has not improved. Therefore, the sensor circuit must be refined. To save 1 resistor or capacitor, you must remove it. This is a question that many engineers planning sensors are easy to ignore. The known situation is that the sensor circuit is confused with the question of noise, and the more the circuit is corrected, the more chaotic it becomes.

3. Power consumption questions. The sensor is usually at the front end of the subsequent circuit, and there may be long-term lead connections. When the power consumption of the sensor is large, the connection of the leads will introduce all the unnecessary noise and the power supply noise, making the subsequent circuit difficult to plan. In the case of a small enough situation, how to reduce power consumption is also a big test.

4, the choice of yuan equipment and power circuit. The selection of the yuan equipment must be sufficient, only the equipment indicators can be within the scope of the demand, and the rest is the circuit planning question. Power supply is a difficult problem in the sensor circuit planning process. Don't seek power supply indicators that cannot be achieved. Choose an op amp with better common-mode rejection ratio. Use differential expansion circuit to plan perhaps the most common switching power supply. The equipment will be able to satisfy your request. The retreat of the power supply must be firmly planned, and in accordance with the request of the equipment manual, Ningduo should not be less.